GREEN BAY — The Green Bay Water Utility has applied to the Public Service Commission to raise water rates.

The utility is seeking a 9 percent rate hike, which would mean about an additional $1.44 per month on the average residential user’s water bill, according to the utility.

The purpose for the increase is to cover rising costs and to implement the utility’s new plan for a more aggressive pipe-replacement schedule, director Nancy Quirk said.

The utility has 440 miles of pipe in the ground, some of which are more than 100 years old, and it had been working on a schedule of replacement of about 2.5 miles a year, Quirk said. The utility is also in the process of replacing the last of the city's lead service lines, a project that is expected to be completed in 2021.